Investment casting is a cost-effective process for many industries that are looking for high-precision metal parts made from a variety of alloys. The typical process for making a casting is to use a wax pattern, which is covered in a ceramic slurry to form the shell. The shell will then be filled with molten metal and cooled to form the part.
The creation of wax patterns is usually done by using metal molds, as the injected wax fills the mold. Water soluble or ceramic cores will create intricate internal parts in the mold. However, more and more industries are looking at 3D printed investment casting as a more cost-effective method.

What is a 3D printed casting model?
Many industries can use 3D printers to create products made of materials such as plastic. However, these machines can 3D print resin, metal and even food parts for certain industries. For investment casting, wax or resin plastics can be chosen depending on the manufacturer and its available equipment.
For 3D printing, a stereolithography (SLA or SL) process is used. Stereolithography is an additive manufacturing technique that takes material and lays it down layer by layer to create patterns. Each layer is cured using UV light or a laser until the entire pattern is created. This process is also known as vat aggregation.
When the pattern is complete and covered in the ceramic slurry, the wax will be melted or the resin will be burned out. Any remaining ash will be removed during the cleaning process.

Benefits of 3D Printing Patterns
A major benefit is that 3D printing patterns is an additive production process that uses only a certain amount of material to create the pattern. This factor eliminates the waste typically created using subtractive manufacturing methods. Because material is added in layers, patterns with highly complex geometries and intricate shapes can be designed without compromising overall pattern creation cost.
Another benefit is that 3D printing can be used to make the patterns needed for prototyping. The Prototype pattern can be easily dropped into components for testing without breaking the application. This process allows customers and fabricators to make necessary changes early in the investment casting process before full production begins.

When to Use 3D Printed Models for Investment Casting
Investment casting with 3D printed models is often sought when customers do not want or need secondary machining of the casting. The process often produces complex parts that are highly accurate and have smooth surfaces. It's also ideal when customers are on tight schedules for parts, since they don't have to wait for the manufacturer to create the right tooling for the process.
3D printed models are of great advantage when low-volume production runs and prototypes are required. If customers know that designs will vary, using 3D printing technology can speed up the process while reducing material waste.